Traditions and ethos have a way of transforming most noble intentions religious practices. And that is why for many cults, the conservation of ecology takes place in the form of nature worship.
A patch of land, the size of which can vary anywhere between a band of few trees to as much as twenty hectares, which is preserved by a religious group is known as sacred grove. All forms of vegetation in such a sacred grove, including shrubs and climbers are under the protection of reigning deity of that grove, and the removal, even of dead wood, is taboo. (Gadgil and Vartak)

These groves are present all over the world and in India about 13,720 have been documented. There are still many more that are tucked away in the jungles, unknown to formal studies. If all of them are included, the number is speculated to be as high as 1, 50,000.
They have been in existence since the hunting-gathering stage of the society, as there are literary accounts of their presence in Hindu scriptures like the Puranas. Religious sentiments attached to trees and other forms of vegetations may have been the reason for sanctifying an area in the forests. Since that patch of land is untouched, most of these groves include vegetation that dates back to the pre-agrarian era.
Most of the cults around which these groves exist are mother goddess cults. The presiding deity is believed to mete out punishments to any offender who dares to defy the laws laid down by the community. Sacrificing human and animal life sometimes becomes imperative to placate the angered deity. The Attonga tribe in West Africa, punish the wrongdoer by making him dress and live like a woman for the rest of his life, since the rites of the cult are performed by the sisterhood of priestess.
These natural sanctuaries have managed to protect forest cover for ages. In fact, rare and other plants with medicinal value are present only in these groves. For the local population, they are the source of local drugs. Apart from this, it is a refuge for the forest animals and birds. Not only do they safeguard the flora and fauna of the place, but they also provide for a natural laboratory for experiments and studies on ancient species of plants. Many of them also provide water resources in the form of streams and ponds. The overall soil fertility is enhanced leading to a balance in the local ecology.
With the setting in of urbanization and commercialization, these groves are slowly being destroyed. The economic value of the timber and wood in the forests has not escaped the notice of the villagers who were once the guardians of the forests. The underlying value system that once led to the formation of these sacred groves is slowly becoming obsolete, and with it so are these ecological treasures.